On this day 20 years ago, the Soviet Union ceased to exist. And on this anniversary, political changes, albeit on a much smaller scale, are afoot in Russia. Voters cast ballots in a parliamentary election earlier this month that, at least officially, gave the ruling party a majority. But citizens saw ballot box stuffing and other fraud, and responded with the biggest street protests since the Soviet collapse.

Yesterday, tens of thousands of people again rallied in the center of Moscow to demand a re-run of the election. They also called for Prime Minister Vladimir Putin to go.

Peter van Dyk reports from Moscow:

(SOUNDBITE OF A PROTESTER)

PETER VAN DYK, BYLINE: The organizers have just announced there are 120,000 people here. I'm in the middle of the crowd, I can't possibly tell. But I can tell one thing - Russia has never seen anything like this.

The police said 29,000 people came. Whatever the numbers, the Kremlin can't ignore them. They are not radicals. They are not revolutionaries. They are Russia's middle class.

Dmitry Trebulyev works in advertising.

DMITRY TREBULYEV: (Through Translator) I'm just sick and tired of what's been going on. And I think that something has to be done to make sure that they go, basically. I don't believe they can afford any real change. For the change to happen, they must go. That's the only way.

(SOUNDBITE OF CHEERING PROTESTERS)

DYK: The speaker the crowd is waiting for is Alexei Navalny. The anti-corruption blogger was jailed for 15 days after the first protest against fraud in the parliamentary elections that were held on December 4th. Now he's back and getting the crowd going.

(SOUNDBITE OF CHANTING PROTESTERS)

DYK: We won't forget, we won't forgive, they chant. Dmitry Trebulyev compares the feeling at the rally to the final months of the Soviet Union, when he was in his late 20s.

TREBULYEV: The atmosphere is great. I mean I just love it. I haven't experienced anything like that since '91.

(SOUNDBITE OF LAUGHTER)

DYK: Exactly 20 years ago, Mikhail Gorbachev accepted the inevitable, and signed the USSR out of existence.

KONSTANTIN VON EGGERT: This is not 1991, in a sense that no one wants to bring down the system. No one wants to dismantle it.

DYK: Konstantin von Eggert is a political commentator on Kommersant FM Radio. He says these protests are lead by 20 and 30-somethings.

EGGERT: They've decided that not only they are satisfied with leading a very comfortable, if not affluent and bourgeois lives, but also that this should correspond to a certain set of political rules.

DYK: Even after just three weeks, the protests are having an effect. The main television news used to show protesters in a very bad light. Now, shockingly for many people here, coverage of the protests is relatively neutral.

Media analyst Alexei Pankin says it's probably a lasting change.

ALEXEI PANKIN: I think that they, the authorities, realized that the way the protesters were covered before, immediately after the elections, was a major irritation for them.

DYK: The Kremlin is also promising political change, making it easier for political parties or presidential candidates to register. It's not enough for the protesters, but it may be enough to guarantee Vladimir Putin victory in the first round of the March presidential elections.

Konstantin von Eggert says that is the worst thing Putin could wish for.

EGGERT: He needs to go for a second round. He should pray for a runoff, especially against communist leader Gennady Zyuganov, because then I think lots of people will have second thoughts about who they really want as president. And then Putin could come out of this election, say, look, we have changed the country and I was part of it. And I have new legitimacy. Because what we see in Russia today, make no mistake about it, it is a legitimacy crisis for Putin and the system that he has built.

(SOUNDBITE OF A PROTESTER)

DYK: Twenty years after the Soviet Union broke apart, Von Eggert says Russia is again being remade. The protesters feel it too.

(SOUNDBITE OF CHANTING PROTESTERS)

DYK: We will come again, they chant. They are determined not to let this moment slip away.